Digital door keeper exchanger for digital Duo System. Amongst the available functions: communication between internal and external stations, auto insertion on external door station, day/night shunted switching, users groups, insertion on a busy user, call by 'alias' number instaed of physical address, opening of many doors even on non-specific demand, agenda, master/slave auto setting, event list log on memory card, call queuing and booking of not managed calls, suitable also for projects with multi-concierges. On systems with wide number of users (DUO extended range), in combination with 2231Q insulators, it allows to manage calls to specific "block". For the complete video version, as showed in the picture, add the screen monitor ST7100CW, the bracket WB7260 and the table adapter TA7100W.